Encephalopathy Secondary to a Surgical Splenorenal Shunt

Abstract

Case: A 56 year old female with history of portal hypertension(PH) secondary to scleroderma (CREST variant) complicated by recurrent esophageal variceal treated by a surgical splenorenal shunt and splenectomy six months prior to presentation was admitted for confusion. Vital signs were within normal limits. Physical exam was notable for mild encephalopathy and asterixis. Labs on admission showed alkaline phosphatase of 154 and ammonia of 288; CBC, BMP, and other liver enzymes were normal. A work up for infection including chest X-ray, urinalysis and blood cultures was negative. CT head was negative for any acute process. CT angiography demonstrated widely patent splenorenal shunt with a decrease in size of the portal vein and preferential drainage into the splenic vein; thus causing minimal hepatic clearance. Patient was started on lactulose and rifaximin with immediate improvement of symptoms. Few weeks later, patient underwent an endovascular splenorenal shunt closure by interventional radiology. Post procedural imaging showed patent portal vein flow. Discussion: Hepatic encephalopathy(HE) is a spectrum of reversible neuropsychiatry abnormalities in patients with liver dysfunction. The exact mechanism of HE is not well understood but thought to be due to an increase in the ammonia level. Typically, hyperarammonemia is seen in cirrhotic patients with PH. However, there several etiologies for non-cirrhotic portal hypertension (NCPH) exist. Pathophysiology behind NCPH is vascular in nature and attributed to endothelial cell lesions, intimal thickening, thrombotic obliterations, or scarring of the intrahepatic portal or hepatic venous circulation. One rare cause of NCPH is scleroderma, an autoimmune connective tissue disease with features including vascular injury and fibrosis of skin and various internal organs including the liver. The main treatment of NCPH is aiming to decrease PH; this can be done surgically by creating portosystemic shunts. In our case, a preferential flow into the shunt and away from the portal vein caused decrease hepatic clearance leading to HE. Although surgical shunts are a rare cause of hyperammonemic encephalopathy, this case highlights the importance of a thorough work up in patients presenting with new encephalopathy.